The present invention relates to a longitudinal quartz crystal resonator comprised of a vibrational portion and a support portion, which are formed integrally by an etching process. More specifically present invention relates to a longitudinal quartz crystal resonator having a new shape suitable for a clock signal source of a portable instrument such as an IC card, a pager or a movable communication device, which require reduction in size and power consumption.
In the conventional longitudinal quartz crystal resonator comprised of a vibrational portion and a support portion which are integrally formed by an etching process, the vibrational portion is composed of a single vibrating arm, thereby failing to reduce a series resistance R.sub.1. The conventional longitudinal quartz crystal resonator having a single vibrating arm has therefore a relatively small overall mass. Therefore, the conventional resonator suffers from asymmetricity of shape caused by the etching process due to structural anisotropy of the quartz crystal. The asymmetricity of shape may affect oscillating performance. In view of this, the conventional resonator has a relatively great vibrational energy loss through the support portion, thereby causing serious problems such as increase in the value of R.sub.1. Further, there remains simultaneously another problem that oscillation starting response is relatively slow due to a great amount of an equivalent inductance L.sub.1. There has long been desired a longitudinal quartz crystal resonator having small values of R.sub.1 and L.sub.1.